Tennessee CDL General Knowledge Practice Test

The Tennessee CDL test has 50 questions. You must answer at least 40 correctly — 80% — to pass. TDOSHS (Tennessee Department of Safety and Homeland Security) administers CDL testing at driver services centers and approved third-party sites throughout Tennessee.

Tennessee CDL holders operating a commercial motor vehicle are subject to the federal 0.04% BAC limit — half the standard adult DUI threshold of 0.08%. A DUI conviction in any vehicle triggers CDL disqualification: 1 year for a first offense, lifetime for a second. Tennessee's implied consent law also applies — test refusal results in a 1-year revocation.

Tennessee's Hands-Free Act (effective July 1, 2019) bans all handheld device use while driving — including for CDL operators in commercial vehicles. Commercial drivers also face federal FMCSA penalties up to $2,750 per violation. Fines in school zones and emergency zones are doubled. Both state and federal penalties apply simultaneously, and violations appear on the driver's PSP record.

Tennessee's CDL test includes questions on mountain driving for Appalachian and Smoky Mountain grades: (1) downshift to a lower gear BEFORE the descent — don't wait until you need to slow; (2) use engine braking as primary speed control; (3) apply service brakes briefly and intermittently (snub braking); (4) never ride the brakes continuously — brake fade causes complete failure on long descents; (5) use runaway truck ramps if brakes fail.

A Tennessee CDL is valid for 8 years. Your DOT medical certificate must remain current throughout the validity period. HazMat endorsements require TSA security clearance renewal every 5 years. Tennessee CDL holders must self-certify their medical status category annually at TDOSHS driver services.

A Class A CDL allows you to operate any combination of vehicles with a Gross Vehicle Weight Rating (GVWR) of 26,001 lbs or more, provided the towed unit exceeds 10,000 lbs — this includes tractor-trailers and double/triple trailer rigs. A Class B CDL covers single vehicles with a GVWR of 26,001 lbs or more, or any such vehicle towing a unit not exceeding 10,000 lbs — this includes straight trucks and large buses. A Class C CDL is required for vehicles designed to carry 16 or more passengers (including the driver) or for vehicles transporting hazardous materials that require placarding, when those vehicles do not qualify for Class A or B.

CDL fees vary by state and by the class and endorsements you obtain. Most states charge separate fees for the CDL knowledge test ($10–$30 per attempt), the CDL skills test ($50–$150), and the CDL license itself ($50–$100). Additional fees apply for each endorsement (HazMat, Tanker, Passenger, etc.). The HazMat endorsement also requires a TSA security threat assessment fee of approximately $86. Check your Tennessee DMV website for current fee schedules.

Federal regulations (49 CFR 383.133) require that CDL applicants be able to read and speak the English language sufficiently to understand highway traffic signs and signals and to respond to official inquiries. Many states offer CDL knowledge tests in Spanish and other languages for non-commercial knowledge questions, but the actual CDL test must be taken in a language that allows the driver to meet the English proficiency requirement. Check with the Tennessee DMV for available language options.

In most states, a CDL is valid for 4–8 years (commonly 4–5 years). To renew your Tennessee CDL, you typically need to visit a DMV office, pass a vision test, pay the renewal fee, and update your medical certification (DOT physical). If you hold a HazMat endorsement, your TSA background check must also be current. CDLs cannot generally be renewed online due to federal requirements for in-person verification of medical certification.

If you fail the CDL General Knowledge test in Tennessee, you are typically required to wait a specified period (commonly 1–7 days) before retaking it. Most states allow 2–3 attempts before requiring additional waiting periods or study requirements. There is usually a retest fee for each attempt. Focus on the areas you missed — most states provide a score sheet showing which topic areas you need to review.